20 lines
530 B
Text
20 lines
530 B
Text
program HaversineDemo;
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uses Math;
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function HaversineDist(th1, ph1, th2, ph2:double):double;
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const diameter = 2 * 6372.8;
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var dx, dy, dz:double;
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begin
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ph1 := degtorad(ph1 - ph2);
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th1 := degtorad(th1);
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th2 := degtorad(th2);
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dz := sin(th1) - sin(th2);
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dx := cos(ph1) * cos(th1) - cos(th2);
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dy := sin(ph1) * cos(th1);
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Result := arcsin(sqrt(sqr(dx) + sqr(dy) + sqr(dz)) / 2) * diameter;
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end;
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begin
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Writeln('Haversine distance: ', HaversineDist(36.12, -86.67, 33.94, -118.4):7:2, ' km.');
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end.
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